The present invention pertains to drive systems for roller pumps used by surgeons in cardiopulmonary bypass operations to perfuse a patient's body with blood passed by means of tubing through an oxygenator for removal of carbon dioxide and addition of oxygen to the blood so that the patient's lungs and heart may be immobilized for surgical procedures. More specifically, this invention relates to a portable auxiliary drive system for such a pump for use in the event of a sudden failure of the normal roller pump drive. The novel drive system includes an adapter unit for quickly engaging the failed pump's rotor, a base unit carrying the drive motor which is placed directly on the failed pump, a connecting unit for connecting the drive motor to the adapter, and a regulation unit for controlling the motor speed.